SVG.Pattern = SVG.invent({
  // Initialize node
  create: 'pattern'

  // Inherit from
, inherit: SVG.Container

  // Add class methods
, extend: {
    // Return the fill id
	  fill: function() {
	    return 'url(#' + this.id() + ')'
	  }
	  // Update pattern by rebuilding
	, update: function(block) {
      // remove content
      this.clear()
      
      // invoke passed block
      if (typeof block == 'function')
      	block.call(this, this)
      
      return this
		}
	  // Alias string convertion to fill
	, toString: function() {
	    return this.fill()
	  }
  }
  
  // Add parent method
, construct: {
    // Create pattern element in defs
	  pattern: function(width, height, block) {
	    return this.defs().pattern(width, height, block)
	  }
  }
})

SVG.extend(SVG.Defs, {
  // Define gradient
  pattern: function(width, height, block) {
    return this.put(new SVG.Pattern).update(block).attr({
      x:            0
    , y:            0
    , width:        width
    , height:       height
    , patternUnits: 'userSpaceOnUse'
    })
  }

})